Conventionally, a power supply system is known, which includes a first DC-DC converter connected to a fuel cell, and a second DC-DC converter connected to a electric storage device, wherein the power supply system supplies electric power from the first and second DC-DC converters to a load such as an electric motor for driving motor vehicles (refer to, for example, Patent Document 1).
In addition, a device is known, in which a plurality of chopper devices are connected in parallel (refer to, for example, Patent Document 2).